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Clojure at Netflix (2013) [slides]

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Re: Clojure at Netflix (2013) [slides]

#171

Post by justinhj »

m12k wrote: post #55

I'd like to learn a modern production-ready functional language (I have some academic experience with SML), since they seem like a good way to grow as a programmer. Main contenders so far are Haskell, Scala and Clojure (Reason might go on the list soon too) - but the fact that Clojure is dynamically typed is a bit of a turn off for me. My experience with dynamic vs static typing is that as a system grows in size and…

Scala is sometimes referred to as the Haskellator, in that once you get far enough down the pure functional programming road, you may find yourself wanting to switch to Haskell. Scala doesn't enforce pure functional programming as much as Haskell. On the other hand I believe that Scala is much more widespread in industry because it's easy to sneak it in the door as an OOP/imperative language that just happens to have good support for higher kinded types, immutable data and other fp features. My advice, if it's for your own personal learning and possibly for some small in-house projects learn Haskell. If you want to use it for a large project with developers that are interested in learning fp but not yet fully committed learn Scala.

Also, yes, any dynamic language suffers from difficulties with refactoring, runtime errors, needing lots of test coverage and not scaling well to large teams and codebases. IMHO

Re: Clojure at Netflix (2013) [slides]

#172

Post by flavio81 »

kbp wrote: post #126
diab0lic wrote: post #115

Earlier quoted context omitted.

And now that I've responded to the GP, to address your points: > that means clojure is still being used for new projects, or not? This has been / will always be a professional choice of the engineer(s) starting a new project at Netflix. Clojure is great for a lot of reasons and lets you target JVM/NodeJS at the same time (our two largest backend languages) but as a LISP most people aren't going to be excited about us…

> but as a LISP most people aren't going to be excited about using it. I agree that Clojure has a lot of strong points and that s-expressions probably put a lot of people off, but as a Lisp programmer, I was very disappointed in Clojure's debugging/interactive development story (and I've heard that from a lot of others). It feels more like using a typical scripting language compared to the traditional Lisp/Smalltalk…

> I was very disappointed in Clojure's debugging/interactive development story (and I've heard that from a lot of others). It feels more like using a typical scripting language compared to the traditional Lisp/Smalltalk experience

Common Lisp user here. I was also disappointed in the same way when trying Clojure.

Other minor things i didn't like was the noisy [] on the syntax, and the fact that for practical purposes you're fully tied to the JVM and the java runtime libs.

Re: Clojure at Netflix (2013) [slides]

#173

Post by fazzone »

tanin wrote: post #166
KingMob wrote: post #61

Earlier quoted context omitted.

I use Clojure in the large, and the lack of static typing isn't something I miss. FWIW, spec allows you make similar guarantees if you use it (technically more, since you can express more than HM type systems). I think the static/dynamic divide speaks to deep divisions in programmer personalities, but if you're open to suggestion, I would put it like this: As Haskell/OCaML are to static langs like Java, Clojure is to…

Is Spec simply a test? Or is it something more? I keep hearing about it, but it seems to be more than just a test case. Let's take a simple example. I have an object with the method named "get". But I call "fetch" in my code. When will I see this error? During compile time or run time?

In Clojure unresolved names are a compile failure, and Spec would not be involved. Spec is just a nice library for writing runtime assertions about data. An example would be calling a third-party API and then validating the response with Spec to make sure it matches your expectations, or even validating the responses you are about to return from your own API. Similar to a type system the Spec can also serve as a sort of documentation about what's in the data structure.

Re: Clojure at Netflix (2013) [slides]

#174

Post by jrochkind1 »

KingMob wrote: post #61
m12k wrote: post #55

I'd like to learn a modern production-ready functional language (I have some academic experience with SML), since they seem like a good way to grow as a programmer. Main contenders so far are Haskell, Scala and Clojure (Reason might go on the list soon too) - but the fact that Clojure is dynamically typed is a bit of a turn off for me. My experience with dynamic vs static typing is that as a system grows in size and…

I use Clojure in the large, and the lack of static typing isn't something I miss. FWIW, spec allows you make similar guarantees if you use it (technically more, since you can express more than HM type systems). I think the static/dynamic divide speaks to deep divisions in programmer personalities, but if you're open to suggestion, I would put it like this: As Haskell/OCaML are to static langs like Java, Clojure is to…

I believe you (I'm a ruby programmer, so you know I'm not strict about typing), but can you clarify -- `spec` is runtime, not statically typed, true?

Re: Clojure at Netflix (2013) [slides]

#175

Post by cutler »

tosh wrote: post #28
nerdponx wrote: post #3

What happened to Clojure? Was it just a fad, or are people still using it in their day jobs? Are people still hiring Clojure devs? If you write Clojure at work, are you happy with it?

According to the JVM Ecosystem report/survey Clojure is the 2nd main language on the JVM (after Java): https://snyk.io/blog/jvm-ecosystem-report-2018 ClojureScript also seems to gain traction. Quite impressive when you consider that Clojure is a language/ecosystem not driven/backed by one of the larger tech companies.

See my earlier post in response to yogothos. On jobs boards Scala adoption is orders of magnitude higher than Clojure.

Re: Clojure at Netflix (2013) [slides]

#176

Post by trevor-e »

zeveb wrote: post #163
trevor-e wrote: post #157

Earlier quoted context omitted.

How does this work with autocomplete if you need to know the method name before the object you're working with? Maybe I'm not getting something but that sounds incredibly painful to use in practice.

In Common Lisp, it works because symbols are scoped by package, not by object. So if you're in the package foo and start typing 'bar,' then your editor would autocomplete symbols in the foo package starting with 'bar'; likewise if you typed 'baz:quux' your editor autocomplete would autocomplete symbols in the baz package starting with 'quux.' Common Lisp most definitely doesn't have one namespace; this is really nice…

OK so my confusion was from thinking Clojure is statically typed, which apparently is not true. I was basically asking the same question as https://www.reddit.com/r/Clojure/comments/6f6cq2/how_to_comp...

Re: Clojure at Netflix (2013) [slides]

#177

Post by ahjones »

tanin wrote: post #166
KingMob wrote: post #61

Earlier quoted context omitted.

I use Clojure in the large, and the lack of static typing isn't something I miss. FWIW, spec allows you make similar guarantees if you use it (technically more, since you can express more than HM type systems). I think the static/dynamic divide speaks to deep divisions in programmer personalities, but if you're open to suggestion, I would put it like this: As Haskell/OCaML are to static langs like Java, Clojure is to…

Is Spec simply a test? Or is it something more? I keep hearing about it, but it seems to be more than just a test case. Let's take a simple example. I have an object with the method named "get". But I call "fetch" in my code. When will I see this error? During compile time or run time?

This is spec: https://clojure.org/about/spec

All spec errors turn up at run time. See the guide for more details: https://clojure.org/guides/spec.

You can combine spec with test.check (Clojure's quick check library) https://clojure.org/guides/spec#_generators

Re: Clojure at Netflix (2013) [slides]

#178

Post by fiddlerwoaroof »

michaelmrose wrote: post #145
diab0lic wrote: post #134

Earlier quoted context omitted.

Oh, yes this is another excellent example of pain while building Clojure code bases. Though I'll say I only agree with half of your statement. I've found the interactive development story to be great with nrepl/fireplace/vim but the debugging is downright terrible... this is the single biggest blocker to me using it for larger systems.

Debugging seems acceptable on emacs with cider. Sayid seems interesting as well.

Yeah, cider has an amazing form by form debugger for Clojure. And the way cider uses overlays to surface this is quite nice too.

My general experience of cider is that for a certain set of tasks it is much better than slime. But, the problem is, most of my day-to-day coding tasks are hampered by the language: e.g. if I have a web server running and I want to change a request handler, you can’t just recompile the handler, you also have to restart the server.

Re: Clojure at Netflix (2013) [slides]

#179

Post by lgessler »

tanin wrote: post #166
KingMob wrote: post #61

Earlier quoted context omitted.

I use Clojure in the large, and the lack of static typing isn't something I miss. FWIW, spec allows you make similar guarantees if you use it (technically more, since you can express more than HM type systems). I think the static/dynamic divide speaks to deep divisions in programmer personalities, but if you're open to suggestion, I would put it like this: As Haskell/OCaML are to static langs like Java, Clojure is to…

Is Spec simply a test? Or is it something more? I keep hearing about it, but it seems to be more than just a test case. Let's take a simple example. I have an object with the method named "get". But I call "fetch" in my code. When will I see this error? During compile time or run time?

Think of it this way: spec gives you an easy way to ensure that your data conforms to arbitrary predicate functions.

Suppose you have an XML format, that has books and authors[1]. The elements look something like this: , . Obviously, you want to make sure that book's author-id attribute will always refer to an author that actually exists. This is something a (Java-style) static type system can't do: it doesn't know at compile-time what the contents of a variable will be. But spec can do this because it is a runtime check[2]: you'd just write a function that ensures all author-ids refer to extant authors and register it with spec, telling it that this must be true for valid s.

As for your example, I don't think that is a use-case that spec was intended to handle. You could write a spec to ensure that an object has certain properties/methods, but I'm not spec would be too useful for a function invocation on that object.

[1]: For a worked out example of this in spec, see a blog post I wrote: https://lgessler.com/posts/2018-07-12-choosing-the-right-too...

[2]: It sounds expensive, but there's a compiler flag that lets you turn off all spec checks, so you can have them only run in dev builds if you like.

Re: Clojure at Netflix (2013) [slides]

#180

Post by fiddlerwoaroof »

fiddlerwoaroof wrote: post #178
michaelmrose wrote: post #145

Earlier quoted context omitted.

Debugging seems acceptable on emacs with cider. Sayid seems interesting as well.

Yeah, cider has an amazing form by form debugger for Clojure. And the way cider uses overlays to surface this is quite nice too. My general experience of cider is that for a certain set of tasks it is much better than slime. But, the problem is, most of my day-to-day coding tasks are hampered by the language: e.g. if I have a web server running and I want to change a request handler, you can’t just recompile the hand…

(Although, if you anticipate this, you can call the ref (e.g. `(#’foo arg)`) rather than the function `(foo arg)`. But this means that you have to plan the dynamically modifiable parts out ahead of time.
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